Furuno FELCOM251, Installation Manual

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2. INSTALLING THE SYSTEM
2-10
High masts or installations on ships with high vibration levels should be further stabi-
lized by stays or wires from the mast flange. Also mount vibration isolators between
the flange and the radome, as described in section 4.9.2. For FELCOM251, the vibra-
tion isolators are included in the Mast mount kit.
Note: Stays and rigid masts can still not prevent vertical vibration if the mast is at-
tached to a deck plate that is not rigid. Make every effort to mount the mast on a sur-
face that is well supported by ribs. If this is not possible, provide extra deck plate
propping.
FELCOM501 Antenna Unit mast length for FB-1501
The below table shows the values for a FELCOM501 Antenna Unit mast without stays
or wires. Note that these values are only guidelines – always consider the environment
and characteristics of the ship before deciding on the mast dimensions.
Antenna Unit mast length FELCOM501
*: FB-1501: The diameter of the circle where the bolts are to be mounted on the an-
tenna is

282.8 mm. Since the mast diameter is larger, you must use a tapered end
on the mast, or find other means of accessing the mounting bushings.
OD(mm)
Wall
Thickness(m
m)
Weight (kg/m)
Inertia
(X10
6
mm
4
)
Max. free mast
length
(steel, m)
88.9 4.05 8.47 0.974 < 0.9
88.9 4.85 10.1 1.14
100 5 11.7 1.69 < 1.0
101.6 5 11.9 1.77
114.3 4.5 12.1 2.34 < 1.2
114.3 5.4 14.4 2.75
139.7 4.85 16.1 4.68 < 1.4
139.7 5.4 17.9 5.14
165.1 4.85 19.2 7.85 < 1.6
165.1 5.4 21.3 8.65
300
* 7.5 54.1 73.75 < 2.7
300
* 15 105.4 136.7